The present disclosure relates to an apparatus for substrate alignment, an apparatus for substrate processing having the same, and a substrate alignment method, and more particularly, to an apparatus for substrate alignment capable of precisely and automatically aligning a mask on a substrate by sequentially moving the substrate and the mask in a horizontal direction on a susceptor being driven up and down, an apparatus for substrate processing including the apparatus for substrate alignment, and a substrate alignment method.
Recently, a variety of flat panel display devices to replace a cathode ray tube are being developed and produced. A liquid crystal display (LCD), a field emission display (FED), an electroluminescent display (ELD), a plasma display panel (PDP), and so forth belong to the flat panel display.
Especially the ELD having a solid state property features a relatively wide range of use temperature, high impact-resistance and vibration-resistance, a wide viewing angle, and a fast response time. Therefore, the ELD is generally used as a high-performance flat panel display.
The ELD may be classified into an inorganic light emitting diode (ILED) and an organic LED (OLED) according to materials constituting an emitting layer. The OLED is widely used in recent days since it has superior luminance and response time to the ILED and is capable of color-display.
The OLED includes a first electrode layer constituted by a transparent insulation substrate and a predetermined pattern formed thereon, an organic emitting layer disposed on the first electrode layer, containing a luminescent material, and a second electrode layer disposed on the organic emitting layer. Usually, the first electrode layer serves as an anode electrode and the second electrode layer serves as a cathode electrode.
When the anode electrode is applied with a higher voltage than the cathode electrode, a hole moves from the first electrode layer to the organic emitting layer and an electron moves from the second electrode layer to the organic emitting layer. The moved hole and electron combine again at the organic layer, thereby forming an exciton. Energy from the exciton generates light having a specific wavelength.
For example, the organic emitting layer and the second electrode layer may be formed by vapor deposition as follows. A metal mask having a plurality of slits is prepared. The slits are arranged corresponding to a predetermined pattern to be formed on a substrate. In a vapor-deposition chamber, the material is evaporated through the slits and attached to a surface of the substrate.
The vapor deposition is performed as the mask is brought into close contact with the substrate or a predetermined patterned layer of the substrate. Therefore, it is very essential to dispose the substrate and the mask in their correct positions.
FIG. 1 schematically shows methods for aligning a substrate and a mask according to a related art.
Referring to FIG. 1A, first, substrate alignment pins 32 each having an inclined surface A are disposed on outer positions of an upper surface of a susceptor 30 provided in a chamber (not shown). A substrate 10 is slid down along the inclined surfaces A, thereby being seated on the susceptor 30.
The susceptor 30 is driven upward such that the mask alignment pins 32 disposed on the outer positions of the upper surface of the susceptor 30 are corresponded to alignment recesses 22 formed on outer positions of a lower surface of the mask 20.
However, the above related-art method merely using the fixed alignment pins 32 and 34 is available only when alignment margins are allowed. That is, the above method is inadequate when precise alignment between the substrate 10 and the mask 20 is required.
According to another related-art method, as shown in FIG. 1B, the mask 20 including a plurality of slits 24 for vapor-deposition of a predetermined pattern is moved on the substrate 10. During this, an optical microscope 40 or a camera checks whether an alignment mark 12 marked at the substrate 10 is aligned to an alignment hole 26 formed at the mask 20. When aligned, the substrate 10 and the mask 20 are brought into close contact with each other.
However, this method costs a lot of initial installation expenses because of expensive equipment such as the optical microscope 40. In addition, the substrate 10 and the mask 20 need to be in contact or almost in contact with each other for check of the aligned state using the optical microscope 40. Such a contact may damage the substrate 10 or the pattern formed on an upper surface of the substrate 10, accordingly increasing a defect rate of the substrate 10.
In a case where the substrate 10 and the mask 20 are found to be misaligned after the alignment process is completed, the substrate 10 and the mask 20 need to be separated, realigned, and rechecked by the optical microscope 40 and such processes may be repeated. As a result, the overall alignment time increases. Furthermore, since the alignment processes are discontinuously performed, it is hard to perform the alignment rapidly.
In addition, a tube 42 is installed on an optical path in the optical microscope 40 to more closely check the aligned state between the alignment mark 12 and the alignment hole 26. The tube 42 is easily contaminated or damaged by particles generated during processing of the substrate 10. In this case, the tube 42 needs repairing or replacing, consequently inducing additional expense and time.